Antimicrobial and toxicological characteristics of commercial herbal extracts and the antimicrobial efficacy of herbs in marinated chicken

The demand for safe and minimally processed food and nutraceuticals has created a market for natural antimicrobials. Limited studies have investigated herbal medicine\u27s safety, inhibitory and lethality effect to pathogenic microorganisms and the antimicrobial efficacy of herbs in food model systems such as chicken. Our objectives were to evaluate the antimicrobial and mutagenic activities of commercial herbal extracts and to investigate the antimicrobial efficacy of herbs to spoilage and pathogenic bacteria in marinated chicken. Essential oils and/or herbal extracts of bilberry, black cohosh, cranberry, evening primrose oil, flax seed, garlic, ginko, ginseng, goldenseal, gotu kola, grapefruit oil, grapefruit seed (GSE), kava-kava, lemon balm, marjoram, milk thistle, oregano, pau d\u27arco, skullcap, hypericum, thyme, and valerian were evaluated for antimicrobial activity by the disc agar diffusion method. Mutagenicity of selected herbs was determined by the Ames test. The mutagenicity ratio (MR) was calculated based on # revertants/plate as compared to control (MR \u3e 2.0 = strongly mutagenic). The minimum lethal concentration (MLC) was evaluated by the tube dilution method to determine toxicity prior to mutagenicity assay. Fresh chicken breasts were inoculated (~ log 6 CFU/g) with C.jejuni, S. Typhimurium, L. monocytogenes, and E. coli O157: H7. The following marinade treatments (base of water, salt, sodium phosphate, and citric acid; pH 4.5) were evaluated using fresh inoculated chicken breasts (20% marinade by weight of the chicken): control (no herbs), 0.3% of each GSE, oregano essential oil (ORG), thyme essential oil (THY), 1% dried oregano leaves (ORL), and combination of 0.3% of each GSE, ORG, and THY. APC and survival of pathogenic bacteria during storage at 4°C were determined at days 0, 3 ,6, 9,12, and 15. The most effective antimicrobial herbs were oregano (inhibition zone: 37-87 mm, MLC: \u3c200-3125 ppm), thyme (inhibition zone: 42-87 mm, MLC: 200-1563 ppm), and GSE (inhibition zone: 15-66 mm, MLC: 200-6250 ppm). Bilberry, flax seed, milk thistle, pau d\u27arco, and scullcap were the least effective antimicrobial herbs against all bacterial pathogens. Hypericum, ginko, and goldenseal were strongly mutagenic (Average MR= 4.6, 3.4, and 2.1, respectively). Black cohosh, cranberry, gotu kola, GSE, kava-kava, pau d\u27arco, marjoram, oregano, and valerian showed various degrees of weak mutagenicity. ORE marinade was the least effective treatment in inhibiting all microorganisms. The GSE marinade reduced the APC and growth of C.jejuni, (\u3c2 log CFU/g) but did not significantly inhibit S. Typhimurium, E. coli O157:H7, or Z. monocytogenes (P\u3e0.05). THY, ORG, and the combination treatment significantly reduced microbial counts (P\u3c0.05). The combination treatment was the most effective (P\u3c0.05) in reducing APC and E. coli O157:H7, and was highly lethal (~ log 4 CFU/g reduction) to S. Typhimurium, C.jejuni, and L monocytogenes. The mutagenicity data show that some frequently used herbs may also be strong mutagens and thus potential carcinogens. Further genetic toxicology testing is warranted for concentrated herbal extracts such as hypericum, ginko, and goldenseal due to their growing popularity and mutagenicity in the Ames test. Our data suggest that selected herbs have powerful antimicrobial potency both in culture media and chicken marinade and may be used to increase the shelf life and safety of value-added poultry products

Corrosion Performance of Plain and Epoxy-Coated MMFX Bars

The corrosion resistance of ASTM A1035 Type CL (2% Cr), CM (4% Cr), and CS (9% Cr) steel bars produced by MMFX Technologies were evaluated in both cracked and uncracked concrete as well as in the rapid macrocell test. Uncoated bars with 4% and 9% chromium were tested both in the condition received and after pickling at the University of Kansas; coated bars with 2% and 4% chromium were also evaluated after simulating damage typical to that which would occur during normal handling and placement at a construction site. Bars were compared to the performance of conventional (ASTM A615) and epoxy-coated (ASTM A775) reinforcement from previous studies, and a life-cycle cost analysis over a 75-year design life was performed. The uncoated MMFX bars with 4% and 9% chromium exhibited approximately three times the chloride threshold and between 30-66% of the corrosion rate of uncoated conventional reinforcement, with the 9% chromium bars exhibiting better performance than the 4% chromium bars. Pickling of 9% chromium bars significantly improved its corrosion resistance, while pickling the 4% chromium bars provided only mild benefit. Both epoxy-coated bars tested (2% and 4% chromium) exhibited reduced disbondment of the coating at the end of testing compared to conventional epoxy-coated reinforcement. The 4% chromium coated bars also exhibited significantly lower corrosion rates relative to conventional epoxy-coated reinforcement, with corrosion rates between 15 and 30% of that of conventional ECR. Coated bars with 2% chromium performed comparably or slightly better than conventional epoxy-coated reinforcement (depending on the test method), but the differences were not statistically significant. The life-cycle cost analysis found that epoxy-coated MMFX with 4% chromium was the most cost-effective reinforcement of the bars in this study.MMFX Technologies, Inc

Corrosion Performance of Epoxy-Coated MMFX Bars

The corrosion resistance of coated ASTM A1035 Type CL (2% Cr) and CM (4% Cr) steel bars produced by MMFX Technologies were evaluated in both cracked and uncracked concrete as well as in the rapid macrocell test. Coated bars were evaluated after simulating damage typical to that which would occur during normal handling and placement at a construction site. Bars were compared to the performance of epoxy-coated (ASTM A775) reinforcement from previous studies, and a life-cycle cost analysis over a 75-year design life was performed. Both epoxy-coated bars tested (2% and 4% chromium) exhibited reduced disbondment of the coating at the end of testing compared to conventional epoxy-coated reinforcement. The 4% chromium coated bars also exhibited significantly lower corrosion rates relative to conventional epoxy-coated reinforcement, with corrosion rates between 15 and 30% of that of conventional ECR. Coated bars with 2% chromium performed comparably or slightly better than conventional epoxy-coated reinforcement (depending on the test method), but the differences were not statistically significant. The life-cycle cost analysis found that epoxy-coated MMFX with 4% chromium was the most cost-effective reinforcement of the bars in this study.MMFX Technologies, Inc

Performance Evaluation of Corrosion Protection Systems for Reinforced Concrete

In this study the performance of corrosion protection systems for reinforced concrete is evaluated. Conventional bare and epoxy-coated reinforcement are compared with alternative forms of reinforcement–galvanized steel, MMFX steel containing 9% and 4% chromium (ASTM A1035 Type CS and CM steel), and epoxy-coated MMFX steel containing 4% and 2% chromium (epoxycoated ASTM A1035 Type CM and CL steel). Furthermore, corrosion performance of reinforced concrete with partial replacement of cement by 20% fly ash, 40% fly ash, 5% silica fume, 10% silica fume, 20% slag cement, and 40% slag cement in bridge decks containing uncoated conventional steel as well as 40% fly ash, 10% silica fume, and 40% slag cement in bridge decks containing conventional epoxy-coated reinforcement are compared with the concrete bridge decks containing only portland cement along with epoxy-coated and uncoated reinforcement. The corrosion performance of systems are evaluated using bench-scale specimens (Southern Exposure, cracked beam, and beam specimens) and rapid macrocell tests. Macrocell corrosion rates, corrosion potential, and total corrosion rates, which are measured by Linear Polarization Resistance test, are used to monitor the corrosion performance of specimens. Critical corrosion loss required to crack concrete cover in specimens containing galvanized bars and conventional steel are investigated and compared with the results of predictive equations introduced in the literature. The critical chloride threshold of conventional reinforcement in concrete containing different supplementary cementitious materials (fly ash, silica fume, and slag cement) are compared. The chloride contents are measured based on the free chloride content (water soluble chloride) of concrete samples at the level of bar. The life-expectancy and cost effectiveness of a bridge deck constructed with each system are estimated for a 75-year design period based on the obtained results. Results show that galvanized steel exhibits better performance than conventional bars against corrosion; galvanized steel requires over twice the corrosion loss and has an expected-life about three times as long as conventional steel. The average critical corrosion loss to crack concrete with 1-in. cover is found to be approximately 25 µm, very close to the value obtained by O’Reilly’s (2011) predictive equation. While MMFX bare bars show higher corrosion resistance than conventional bars, those with 9% chromium exhibit better corrosion performance than MMFX bars containing 4% chromium; however, critical chloride threshold of both MMFX bars are about three times of that for conventional steel. Although use of galvanized steel and uncoated MMFX bars are more cost effective than conventional steel, they are not as cost effective as epoxy-coated bars. Epoxy-coated MMFX bars containing 2% chromium do not show significant better performance against corrosion compared to conventional epoxy-coated bars; however, those with 4% chromium have an appreciably higher corrosion resistance and life-expectancy than conventional ECR. Using supplementary cementitious materials in concrete enhances the corrosion resistance of the systems; with increasing the amount of SCM, the time to initiation increased and the corrosion rates decreased. Chloride ingress rate is significantly lower in concrete containing SCM compared to those without it, with the lowest rate in concrete with silica fume. Most specimens containing 40% fly ash, 20% slag, 40% slag, and 10% silica fume repassivate after initiation, with corrosion re-initiating at a higher chloride threshold. The initial critical chloride thresholds for slag cement and 40% fly ash specimens are similar to that for 100% ordinary portland cement, but the secondary CCCT values are significantly higher. For 10% silica fume specimens, the initial CCCT value is lower, but the secondary CCCT value is similar to the critical chloride threshold of conventional steel in specimens with 100% portland cement. While using epoxy-coated reinforcement and supplementary cementitious materials separately, increases the life-expectancy and cost effectiveness of a corrosion protection system, using them together exponentially increases the effects

Effect of Supplementary Cementitious Materials on Chloride Threshold and Corrosion Rate of Reinforcement

Supplementary cementitious materials (SCMs) are commonly used as a means of reducing cost, reducing environmental impact, or reducing permeability of concrete, but the current field of research has found mixed results in terms of the resulting time to corrosion initiation and corrosion rate of concrete containing SCMs. This paper examines the time to corrosion initiation, the water-soluble critical chloride corrosion threshold, and the corrosion rate after initiation for uncracked concrete specimens containing cementitious material consisting of 100% portland cement, mixtures with volume replacements of cement by 20% and 40% Class C fly ash, 20% and 40% Grade 100 slag cement, and 5% and 10% silica fume. Specimens had 1 in. (25 mm) concrete cover and a water-cementitious materials ratio (w/cm) of 0.45. Test results show that many specimens containing SCMs exhibited repassivation of the reinforcement after a “first” corrosion initiation. This “first” initiation occurred at chloride thresholds comparable to or lower than the chloride threshold for reinforcement in 100% portland-cement concrete. The reinforcement remained passive for varying lengths of time (from 3 to 50 weeks) before reinitiating. At reinitiation (“final” initiation), specimens with concrete containing SCMs exhibited times to corrosion initiation two to seven times that observed in specimens containing 100% portland cement and corrosion rates after initiation approximately an order of magnitude lower than that observed in specimens containing 100% portland cement. Increasing the amount of SCM generally lowered the corrosion rate after initiation. Chloride thresholds at final initiation for specimens containing fly ash or slag were 66 to 200% higher than that observed for specimens containing 100% portland cement. Chloride thresholds at final initiation for specimens containing silica fume were 40 to 60% higher those observed for specimens containing 100% portland cement

Effect of Supplementary Cementitious Materials on Chloride Threshold and Corrosion Rate of Reinforcement

Supplementary cementitious materials (SCMs) are commonly used as a means of reducing cost, reducing environmental impact, or reducing permeability of concrete, but the current field of research has found mixed results in terms of the resulting time to corrosion initiation and corrosion rate of concrete containing SCMs. This paper examines the time to corrosion initiation, the water-soluble critical chloride corrosion threshold, and the corrosion rate after initiation for uncracked concrete specimens containing cementitious material consisting of 100% portland cement, mixtures with volume replacements of cement by 20% and 40% Class C fly ash, 20% and 40% Grade 100 slag cement, and 5% and 10% silica fume. Specimens had 1 in. (25 mm) concrete cover and a watercementitious materials ratio (w/cm) of 0.45. Test results show that many specimens containing SCMs exhibited repassivation of the reinforcement after a “first” corrosion initiation. This “first” initiation occurred at chloride thresholds comparable to or lower than the chloride threshold for reinforcement in 100% portland-cement concrete. The reinforcement remained passive for varying lengths of time (from 3 to 50 weeks) before reinitiating. At reinitiation (“final” initiation), specimens with concrete containing SCMs exhibited times to corrosion initiation two to seven times that observed in specimens containing 100% portland cement and corrosion rates after initiation approximately an order of magnitude lower than that observed in specimens containing 100% portland cement. Increasing the amount of SCM generally lowered the corrosion rate after initiation. Chloride thresholds at final initiation for specimens containing fly ash or slag were 66 to 200% higher than that observed for specimens containing 100% portland cement. Chloride thresholds at final initiation for specimens containing silica fume were 40 to 60% higher those observed for specimens containing 100% portland cement

Genetic analysis of field and physiological indicators of drought tolerance in bread wheat (Triticum aestivum L.) using diallel mating design

In order to study the inheritance of field, physiological and metabolite indicators of drought tolerance in wheat, an eight-parental diallel cross, excluding reciprocals, was grown in a randomized complete block design (RCBD) with three replications under two different water regimes (irrigated and rainfed). Significant differences were found for yield potential (Yp), stress yield (Ys), stress tolerance index (STI), leaf water potential (LWP), relative water content (RWC), water use efficiency (WUE) and evapotranspiration efficiency (ETE). Yp, RWC and evapotranspiration efficiency (ETE) showed highly significant differences for both general combining ability (GCA) and specific combining ability (SCA), indicating the involvement of both additive and non-additive gene action in their inheritance. Ys, STI and WUE revealed highly significant differences for SCA, hence non-additive gene action was predominant for these traits. The best general combiners with positive effects, for improvement of Yp, Ys, STI, LWP, RWC, WUE and ETE under drought conditions were parents 5, 1, 6, 2, 7, 1 and 2, respectively. The best specific combination with heterobeltiosis over the best parents for improvement of Yp, Ys, STI, LWP, RWC, WUE and ETE were crosses 3 × 6, 2 × 4, 2 × 6, 5 × 8, 2 × 6, 2 × 4 and 1 × 7, respectively indicating that parents of these crosses are genetically diverse. High broad-sense heritability observed for all the traits confirmed that all the traits are more genetic, but because of low narrow-sense heritability the rule of additive part was low.Key words: Drought tolerance, physiological indicators, diallel mating design, genetic analysis

PERFORMANCE EVALUATION OF CORROSION PROTECTION SYSTEMS FOR REINFORCED CONCRETE

In this study the performance of corrosion protection systems for reinforced concrete is evaluated. Conventional bare and epoxy-coated reinforcement are compared with alternative forms of reinforcement–galvanized steel, MMFX steel containing 9% and 4% chromium (ASTM A1035 Type CS and CM steel), and epoxy-coated MMFX steel containing 4% and 2% chromium (epoxy-coated ASTM A1035 Type CM and CL steel). Furthermore, corrosion performance of reinforced concrete with partial replacement of cement by 20% fly ash, 40% fly ash, 5% silica fume, 10% silica fume, 20% slag cement, and 40% slag cement in bridge decks containing uncoated conventional steel as well as 40% fly ash, 10% silica fume, and 40% slag cement in bridge decks containing conventional epoxy-coated reinforcement are compared with the concrete bridge decks containing only portland cement along with epoxy-coated and uncoated reinforcement. The corrosion performance of systems are evaluated using bench-scale specimens (Southern Exposure, cracked beam, and beam specimens) and rapid macrocell tests. Macrocell corrosion rates, corrosion potential, and total corrosion rates, which are measured by Linear Polarization Resistance test, are used to monitor the corrosion performance of specimens. Critical corrosion loss required to crack concrete cover in specimens containing galvanized bars and conventional steel are investigated and compared with the results of predictive equations introduced in the literature. The critical chloride threshold of conventional reinforcement in concrete containing different supplementary cementitious materials (fly ash, silica fume, and slag cement) are compared. The chloride contents are measured based on the free chloride content (water soluble chloride) of concrete samples at the level of bar. The life-expectancy and cost effectiveness of a bridge deck constructed with each system are estimated for a 75-year design period based on the obtained results. Results show that galvanized steel exhibits better performance than conventional bars against corrosion; galvanized steel requires over twice the corrosion loss and has an expected-life about three times as long as conventional steel. The average critical corrosion loss to crack concrete with 1-in. cover is found to be approximately 25 µm, very close to the value obtained by O’Reilly’s (2011) predictive equation. While MMFX bare bars show higher corrosion resistance than conventional bars, those with 9% chromium exhibit better corrosion performance than MMFX bars containing 4% chromium; however, critical chloride threshold of both MMFX bars are about three times of that for conventional steel. Although use of galvanized steel and uncoated MMFX bars are more cost effective than conventional steel, they are not as cost effective as epoxy-coated bars. Epoxy-coated MMFX bars containing 2% chromium do not show significant better performance against corrosion compared to conventional epoxy-coated bars; however, those with 4% chromium have an appreciably higher corrosion resistance and life-expectancy than conventional ECR. Using supplementary cementitious materials in concrete enhances the corrosion resistance of the systems; with increasing the amount of SCM, the time to initiation increased and the corrosion rates decreased. Chloride ingress rate is significantly lower in concrete containing SCM compared to those without it, with the lowest rate in concrete with silica fume. Most specimens containing 40% fly ash, 20% slag, 40% slag, and 10% silica fume repassivate after initiation, with corrosion re-initiating at a higher chloride threshold. The initial critical chloride thresholds for slag cement and 40% fly ash specimens are similar to that for 100% ordinary portland cement, but the secondary CCCT values are significantly higher. For 10% silica fume specimens, the initial CCCT value is lower, but the secondary CCCT value is similar to the critical chloride threshold of conventional steel in specimens with 100% portland cement. While using epoxy-coated reinforcement and supplementary cementitious materials separately, increases the life-expectancy and cost effectiveness of a corrosion protection system, using them together exponentially increases the effects

Corrosion Resistance of Stainless Steel Clad Reinforced Bars

The corrosion resistance of No. 6 Type 316 stainless steel clad bars produced by Commercial Metals Company (CMC) was evaluated using the rapid macrocell and cracked beam tests (15 and 96 weeks, respectively), as described in the Annexes of ASTM A955. The bars were pickled in a 20% hydrochloric acid solution for five minutes, but exhibited some residue after the pickling process. Some bars were sandblasted and repickled at the University of Kansas to remove the residue; these repickled bars were also evaluated in the rapid macrocell test. Both the as received and repickled bars met the requirements of ASTM A955 when evaluated using the rapid macrocell test. Two of the bars evaluated in the cracked beam test exceeded the 0.5 μm/yr, the upper limit for corrosion rate specified in ASTM A955. Upon autopsy of the specimens, it was determined that corrosion only occurred on the cut ends of the bars and not the cladding itself. The stainless steel clad reinforcing bars evaluated in this study met the requirements of ASTM A955. It is recommended that protection of the cut ends of stainless steel clad bars be employed where the use of corrosion resistant reinforcing bars is required.Commercial Metals Compan